JAMB 1998 · UME · Q2

Evaluate $\left[\frac{1}{0.03} \div \frac{1}{0.024}\right]^{-1}$ , correct to 2 decimal places.

Worked solution (try it first)

Dividing by $\frac{1}{0.024}$ is the same as multiplying by 0.024: $\frac{1}{0.03} \times 0.024 = \frac{0.024}{0.03}$ .
Multiply top and bottom by 1000: $\frac{24}{30} = 0.8$ .
The power $-1$ means the reciprocal: $\frac{1}{0.8} = 1.25$ , option B.